title: CYP17 MspA1 polymorphism and age at menarche: a meta-analysis.
abstract: OBJECTIVE
  Literature data on the effects of CYP17 MspA1 polymorphism on age at menarche (AAM) are inconsistent. To reexamine this controversy, we performed a meta-analysis.
  
  
  METHODS
  In total 16 studies containing more than 11000 individuals of various ethnicities were selected for the analyses. For 11 case-control studies, odds ratio (OR) was employed to evaluate the risk of late AAM for each study, using homozygote at the wild-type allele as a control group. For the 5 studies with continuous outcomes, the effect size was estimated using the Hedges' adjusted g, which is calculated based on the standardized mean difference between groups of subjects with early and late AAM.
  
  
  RESULTS
  We did not find evidence for association of the MspA1 polymorphism with AAM in the combined case-control sample with mixed ethnic background (OR=1.03, 95% CI: 0.90-1.18, P=0.66), in the monoethnic case-control sample of Caucasian females (OR=1.09, 95% CI: 0.99-1.20, P=0.08) and in the combined sample with continuous traits (Hedges' g=0.33 and -0.041, 95% CI: -0.14-0.80 and -0.18-0.10, P values 0.17 and 0.56 for the pooled population sample and monoethnic sample of Caucasian females, respectively).
  
  
  CONCLUSIONS
  Our study showed that CYP17 MspA1 polymorphism was not a significant independent risk factor of AAM. Further studies are needed to clarify the effects of the interaction between this gene and other genetic and/or environment factors on AAM.
authors.affiliation: Institute of Molecular Genetics, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, PR China.
authors.forename: Yu-Fang
authors.initials: YF
authors.lastname: Pei
authors.forename: Lei
authors.initials: L
authors.lastname: Zhang
authors.forename: Hong-Wen
authors.initials: HW
authors.lastname: Deng
authors.forename: Volodymyr
authors.initials: V
authors.lastname: Dvornyk
mesh_terms: D000367:Age Factors; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008572:Menarche / Q000235:genetics*; D011110:Polymorphism, Genetic; D012307:Risk Factors; D013254:Steroid 17-alpha-Hydroxylase / Q000235:genetics*
chemical_list: D013254:Steroid 17-alpha-Hydroxylase